For parts you basically want a high end gaming PC[0] + a Valve Index.
SF is probably a great place to find VR Arcades. Googling it looks like there are a couple here is one[1].
Might be better to ask / google around and see which ones have the best reviews.
edit: this one looks good too[2]
[0] https://www.reddit.com/r/buildapcforme/comments/dfpwr0/1000_...